The purpose of this project is to define the regions of brain, the neuronal pathways, and the neurotransmitter systems which control endocrine, metabolic and autonomic responses to internal stimuli (e.g., blood glucose, O2-tension, hormonal state, body temperature, etc.) and to various types of stress (immobilization, foot-shock, hemorrhage, etc.) and the effects of drugs on these systems. The possible role of prostaglandins in control of autonomic function has been examined by studying the effects on cardiovascular parameters of various prostaglandins injected into specific brain areas. Similar studies using opiate peptides which selectively act at Mu or Delta receptors were completed. The role of vasopressin as a neurotransmitter affecting cardiovascular control mechanisms was studied in Sabra hypertension-prone and-resistant strains. Previous observations on the interaction of glucose and dopaminergic neurones have been extended to studies of dopaminergic receptors.